Adjustable head t square



Jan. 15, 1952 o. A. OLSON ADJUSTABLE HEAD T SQUARE Filed Dec. 1, 1949 Patented Jan. 15, 1952 v ED- PATENT o F'F'IlC E zssasiaf ADJUSI ABEE HEAD T SQUARE: Oscar. Antn.0lson, .Ames; Iowa-.- kppiicatibn-Decemberl, 19'l9, Serial No. 130,377

invention; relates to arr adiustablev head? T-square-commonlm usedeonwrectang-ular drafting: boards;

When. using; a -T-square;- on; a-.. drafting boards. itis-ofitendesirable and necessaryttoaproduce rlinesl at. an: angleto any: one 'side of thezboardr This; is, frequently-doneby using-ta triangle in combinationwith:theF-square; but-such 5a method is=;lim.- itedr'tO, a the anglerwhich may be :producedsand: tow the relative shor-tlength; of the. triangle:- These: problems: have herebeforev been: overcome byfthe" use? of a: If-squares with an adjustable head whereby the; rule -may befixed: at any; desired anglento anm Sidfiflfz the board andthe::1ength ;oi thezaline thatcant-be drawn islimitedaonly-rby 'the lengtheofi thesrule: whichwgenerallx is sufficient, for? most, all work: In-myrinvention,- howeverggl have provided a. new andimore-efficient' means for ade justing the: head; on such a T-square'.

Itis, thereforeanobjectof my invention. to: provideaa T-square that can be more-accurately and quickly adjusted on a. drawing; board: at-zany angle to any; side. thereof by providingiiitswithe a: control-means,on-theedge of the eross-piece head portion for eflicientlyadjustably securing oneeof? the cross-head pieces in any: desired set?- position;

A-. furtherobj ect' of this inventionnis torpmvide: a. T-square= of the above character that ihass a pair of calibrated complementary cross-pieces: pivotally, secured: together with. a" rule: rigidly securedto OIIErOfi them and: a control means: capesble of.- engag-ingsone" edge of eaclr of the: crosspieces to; control: the: rotation thereof:

A still furhen ject of? this invention isr'to-a provide: a T-square that is' designed to: eliminate: inkfrom' a drafting-:instrument: adhering thereto: and: therebyoausing smudge on the drawing:-

A" stilL further: object: of :myinventionzisrtoaprovide a: T -squareof thewabove: classeszthati; is? economical; in; manufacture: and": efiicientz. and durable inusei. t

These and other objects will be apparent to those skillediimtheartl My invention consists in the construction, arrangement, and? combination \ofjtli'e various parts of the device, whereby the objects contemplated are attained-as hereinafter more fully set forth, pointed out in my claims, and'illustrate'd' in the accompanyingydrawings; in. which:

Fi l is a top plan view of my T-square showing oneof the movable cross -pieces' positioned at an: angle to thelongitudinal axisof the rule-,1v

Fig; 2 is ar-view ofthe device=-in==invertiedjposie t'ioirfrom-that 1 shown in -Figrland shown positioned on a drawing board,

aolaimsr (c1. aa-ioc) z: Fig. 3ais aircross sectionalview of the rule on this'rT-square taken on' the line 33 of Fig; 2

with dotted linesshow-ing thenposition of a draft ing: instrumenttusinga oneside' of the rule as a guide, and V device board showing a sheet; H for" drawing affixed thereto; It is on suchra boardsthat my -T-square is used;. Thenumerals l2 and I3 respectively designate a-pain of T-squarecross-pieces or--heads thatiare shaped inatherusualiormand-with each having a beveledoutsidez edge 26 on. the central;

convex or arcularportion thereof, as shown in Fig: 1-. These cross-pieces are .ea'chof the samesize: and shape and theztop'side'of each is calibrated .in degree z-so thatthezero reading: willbe at-right: angles. to -the'side that is designed to engage the periphery of the drawing board, as shown-in Fig. 1; r' An elongated rectangulan. preferably: translucent, rule: member is rigidly'secured at one end to the top of the CIOSS-JPiECG' l3 and'ata right angle? thereto by" any; suitable means such as the-screws l5; As shown: in Fig; 4' it should benotedthat the rule is secured on only the inner top; portion of thecross-piece I 3: and terminates a distance from: the outerarcular end of the cross-piece;

The cross-pieces I2 and I3" are pivotally se cured together in spaced relation by the bolt "5* in such a mannerthat-the cross-piece l2 can be rotated in-a plane above and without interference fromnthe rule M: The bolt IB'is preferably ofthe typehavinga male and female portion so that itwi11: tightens on. itself: topivotally secure the cross-pieceslZ-and i'3 without binding the cross pieces-@on-the rule-14,, as shown in Fig; 4.

In: the,- crossepie'cer l3-just tothe rear of therulel4',- I-.provide a wel1 H to accommodate the hookportion lit-of therod i9; as'shown inFig: 4: Therthick-nessof the: rod: l 9* should be'such: that it-"will fitY-in the-space between; the crosspieees: l -2- and: i3 and: beyond therule portion I4. Athreaded portion 2fl onetherod- I9 project's-forwardly and;transversely"beyondfrom convex portion. of these cross-pieces; asshown. in. Fig: 4. This rodwyvill-be heldiin position: by; the crosspieceszl'2 and l3randcanbezremoved only'by-removing-rtherbolt- IE6; andi'its thickness-is approxii-vmately that; of f the: thickness ofr'the' rule M.

The numeral 2| designates a substantially square channel shaped binding bracket that has the inside of each channel edge beveled, as shown in Fig. 4. This bracket is designed to be mounted on the threaded portion of the rod I 9 so that the beveled portions respectively are capable of engaging the beveled edges 26 respectively on the convex portions of the cross-pieces I2 and I3, as shown in Fig. 4. A control nut knob comprising the finger grip portion 22 and rounded boss portion 23 is threaded onto the rod I9 and the rounded end of the boss portion can be tightened against the outside fiat surface of the bracket 2|.

The numeral 24 designates a beveled edge along one longitudinal side of the rule I 4 and the numeral 25 designates a drafting instrument. i

When this T-square is constructed and arranged as described it can be used in the followin manner:

, structure or use of mechanical equivalents which ment with the side edge pf a drawing board, this 1 p'iece I3 and extends therefrom at right angles.

However, whenever it is desired to place the rule I4 on the drawing sheet II at an angle to any side thereof, the control knob can be manually rotated counterclockwise to release the bracket 2| from engagement with the cross-pieces I2 and I3. This will permit the cross-piece I2 to be pivoted and by use of the calibration either on the piece I2 or I3, the piece I2 can be set at any desired angle of degree. When this has been determined the control knob is then tightened so that the channel bracket 2| frictionally engages thebeveled edges on the cross-pieces I2 and I3 to hold the piece I2 at the selected position.

The T-square is then inverted and the crosspiece I2 is placed in engagement withthe periphery of drawing board in the usual manner with the result that the rule I4 will now be at an angle corresponding to the degree to which the cross-piece I2 was pivoted. The above process can be repeated as often as lines at diiferent angles are required and the control knob and bracket will function efficiently to securely hold the new setting each time.

The position of my control knob and bracket at the edge of the cross-pieces has several advantages over present type adjustable head T-squares that usually have curved slots through the crosspieces with a bolt arranged transversely the slots for tightening the head at various positions. In my device the head of the T-square is more economical to construct since no slots. are required. Secondly, since the cross-pieces are not slotted, the calibrations can be more plainly marked and are easier to read. Still another advantage of my T-square is that by arranging the control means at the edge of the cross-pieces they are more efiectively secured in different positions than those devices havin a control means transversely the center portions of the T-square heads.

The reason for this is that the bracket 2| wedges on to the bevels 26 of the heads thereby 'gardless of whether the rule is in inverted or upright position.

may be reasonably included within their scope.

I claim:

1. In a device of the class described, a T-square comprising a cross-piece having one straight edge i ,and aconvex'portion on the other edge, an When the cross-piece I3 is placed in engageelongated translucent rule member secured at one end to said cross-piece and at right angles thereto, a depression in said cross-piece adjacent theend of said rule member, a second cross-piece of the same shape as sa'id first cross-piece and pivotally secured thereto in spaced relation, 'a beveled edge on one longitudinal side of said rule member; a beveled edge on one side of the convex portion ofeach of said cross-pieces,'a rod member threaded on one end and having a hook on the other end; said hook portion resting in said depression and'said threaded portion projecting rearwardly from said cross-pieces, a channel bracket member mounted on said rod member; said channel edges being beveled and capable respectively of engaging the beveled "edges respectively of said cross-pieces at timesand a control knob threaded on said rod and capable of engaging said bracket at times so that tightening of said knob will increase the frictional engagement between said bracket and said cross-pieces.

2. In a T-square, a pair of cross-pieces. pivotally secured together; each of said cross-pieces having one straight edge and a convex portion on the opposite edge thereof; each of said convex portions-having a beveled portion on one edge thereof; a bracket capable of engaging the beveled portions of said convex portions, means to support said bracket and a manually operable means of holding said bracket in engagement with said convexportions and releasing it therefrom.

3. In a T-square, a rule member, a pair of crosspieces one of which is fixed and the other of which is rotatably secured to said rule member; said cross-pieces having a space between them and a well in one of them opening into the space, a rod extending into said space and bent to enter said well, a'binding bracket slidably mounted on said'rod and capable of engaging a portion of the respective edge portions of said cross-pieces and;a means on said rod for forcibly moving said binding: bracket into binding engagement simultaneously with both of said cross-pieces.

OSCAR ANTON OLSON.

' REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Morris July 8, 1947 

